function Snake(ele){
 this.ele=ele
 this.len=20
 this.snakeObj = [
    { x: 3, y :2, color:'plum', ele:null},  //蛇头
    { x: 2, y :2, color:'beige', ele:null}, // 蛇的身体
    { x: 1, y :2, color:'beige', ele:null}  // 蛇的身体
  ]
  this.direction='right'
}
Snake.prototype.remove=function(){
    for(let i=0;i<this.snakeObj.length;i++){
        if(this.snakeObj[i].ele){
        this.ele.removeChild(this.snakeObj[i].ele)
    }
    }
}
Snake.prototype.create=function(){
    this.remove()
    for(let i=0;i<this.snakeObj.length;i++){
        let divObj=document.createElement('div')
        divObj.style.width=this.len+'px'
        divObj.style.height=this.len+'px'
        divObj.style.position='absolute'
        divObj.style.left=this.snakeObj[i].x*this.len+'px'
        divObj.style.top=this.snakeObj[i].y*this.len+'px'
        divObj.style.background=this.snakeObj[i].color
        this.snakeObj[i].ele=divObj
        this.ele.appendChild(divObj)
    }
}
Snake.prototype.move=function(){

    // for(let i=0;i<this.snakeObj.length;i++){
    //     this.snakeObj[i].x+=1
    // }
    for (let i = this.snakeObj.length - 1; i>0; i--) {
        // console.log(this.snakeObj[i])
        this.snakeObj[i].x = this.snakeObj[i-1].x
        this.snakeObj[i].y = this.snakeObj[i-1].y
    }

    switch (this.direction) {
        case 'top':
            /* if(((this.snake[0].x-1)>=0)&&(this.snake[0].x-1)[this.snake[0].x-1][this.snake[0].y]!=2){
                snakeObj={x:this.snake[0].x-1,y:this.snake[0].y}
            } */
             this.snakeObj[0].y -= 1
            break;
        case 'bottom':
            this.snakeObj[0].y += 1
            break;
        case 'left':
            this.snakeObj[0].x -= 1
            break;
        case 'right':
            this.snakeObj[0].x += 1
            break;
    }
    this.create()
}